Germanium-loaded porous hard carbon as well as preparation method and application thereof
By using a method for preparing germanium-supported porous hard carbon, the problem of insufficient electronic conductivity and ion migration rate of porous hard carbon materials in electrochemical applications was solved. A highly efficient electron/ion dual continuous conduction network was constructed, which improved rate performance and cycle stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-03
AI Technical Summary
Porous hard carbon materials have insufficient electronic conductivity and ion migration rate in electrochemical applications, especially poor rate performance at high current densities, which affects their cycle stability and service life.
A method for preparing germanium-supported porous hard carbon was adopted. Oxygen-containing functional groups were introduced into the surface of the porous hard carbon by treating it with an acid solution to enhance its hydrophilicity and binding force. Then, it was reacted with a germanium source solution to form germanium-supported porous hard carbon. Finally, germanium was fixed by calcination in a reducing atmosphere to construct a highly efficient electron/ion dual continuous conduction network.
It significantly improves the electronic and ionic conductivity of porous hard carbon, enhances rate performance, and increases cycle stability and lifespan.
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Figure CN121778698A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium battery anode material technology, specifically to a germanium-supported porous hard carbon, its preparation method, and its application. Background Technology
[0002] Porous hard carbon, as an important carbonaceous functional material, has shown broad application potential in many cutting-edge fields due to its abundant nanoscale pore structure, high specific surface area, and good physicochemical stability. Porous hard carbon materials are typically prepared by high-temperature carbonization of precursors combined with physical or chemical activation methods. Its unique rigid framework structure and well-developed hierarchical pore system make it not only excellent in adsorption separation and catalytic support, but also a promising anode material for electrochemical energy storage devices, particularly attracting significant research attention in novel alkali metal ion battery systems such as sodium-ion and potassium-ion batteries.
[0003] Despite the numerous structural advantages of porous hard carbon materials, several key bottlenecks still hinder their further development in practical electrochemical applications. For example, the electronic conductivity and ion migration rate of porous hard carbon materials need to be improved, especially when charging and discharging at higher current densities, where the rate performance is poor, affecting their cycle stability and service life.
[0004] Therefore, how to improve the surface properties of hard carbon materials and enhance their skeletal conductivity while maintaining high specific surface area and porosity has become a core challenge that urgently needs to be addressed in the current research and development work in this field. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a germanium-supported porous hard carbon, its preparation method, and its application, thereby solving the technical problem of insufficient electrochemical performance of current porous hard carbon materials.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing germanium-supported porous hard carbon, comprising the following steps: S1. The porous hard carbon is immersed in an acid solution, heated and stirred, and then filtered, washed and vacuum dried to obtain pretreated porous hard carbon. S2. The pretreated porous hard carbon is ultrasonically dispersed in a germanium source solution and stirred. Then, a reducing agent is added dropwise, and the reaction is heated. After the reaction is completed, the precursor is obtained by filtration, washing, and drying. S3. The precursor is calcined in a reducing atmosphere. After calcination, it is cooled to room temperature, washed, and vacuum dried to obtain germanium-supported porous hard carbon.
[0007] In the technical solution disclosed in this invention, in step S1, the acid solution is selected from sulfuric acid solution, nitric acid solution or hydrochloric acid solution, and the concentration of the acid solution is 1-5 mol / L. For example, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L or 5 mol / L can be selected, but it is not limited to the listed values. Other unlisted values within the range are also applicable.
[0008] In the technical solution disclosed in this invention, in step S1, the temperature of the heating and stirring treatment is 60-90℃, for example, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, or 90℃ can be selected; the heating and stirring treatment time is 1-6h, for example, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, or 6h can be selected, but it is not limited to the listed values, and other unlisted values within the range are also applicable.
[0009] In step S1, the porous hard carbon is treated with an acid solution to clean the surface of the porous carbon material and introduce oxygen-containing functional groups, thereby enhancing its hydrophilicity and binding force with subsequent active substances. The porous hard carbon is selected from resin-based or biomass-based porous hard carbon.
[0010] In the technical solution disclosed in this invention, in step S2, the ratio of the amount of pretreated porous hard carbon to germanium source solution is 100g:300-600mL, for example, 100g:300mL, 100g:400mL, 100g:500mL, or 100g:600mL; the concentration of the germanium source solution is 0.1-0.5mol / L, for example, 0.1mol / L, 0.15mol / L, 0.2mol / L, 0.25mol / L, 0.3mol / L, 0.35mol / L, 0.4mol / L, 0.45mol / L, or 0.5mol / L, but is not limited to the listed values, and other unlisted values within the range are also applicable.
[0011] Specifically, the germanium source is selected from germanium tetrachloride, germanium nitrate, or germanium oxide.
[0012] In the technical solution disclosed in this invention, in step S2, the reducing agent is selected from NaBH4 solution or hydrazine hydrate.
[0013] In the technical solution disclosed in this invention, in step S2, the pH of the reaction system is controlled between 8 and 10, and the temperature of the heating reaction is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C, or 80°C can be selected; the heating reaction time is 2-4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours, or 4 hours can be selected, but it is not limited to the listed values. Other unlisted values within the range are also applicable.
[0014] In step S2, a reducing agent is added dropwise to the above mixture under stirring to initially reduce the adsorbed germanium ions to low-valence germanium oxide or elemental germanium precursor.
[0015] In the technical solution disclosed in this invention, in step S3, the reducing atmosphere is an H2 / Ar mixed atmosphere, and the volume fraction of H2 is 5-10%, for example, 5%, 6%, 7%, 8%, 9%, 10%, but not limited to the listed values. Other unlisted values within the range are also applicable.
[0016] In the technical solution disclosed in this invention, in step S3, the calcination temperature is 300-500℃, for example, 300℃, 350℃, 400℃, 450℃, or 500℃ can be selected; the calcination time is 1-3h, for example, 1h, 1.5h, 2h, 2.5h, or 3h can be selected, but it is not limited to the listed values. Other unlisted values within the range are also applicable.
[0017] The present invention provides germanium-supported porous hard carbon prepared by the above preparation method.
[0018] The present invention also provides the application of the above-mentioned germanium-supported porous hard carbon in battery anode materials.
[0019] In the technical solution disclosed in this invention, the battery anode material is a silicon-germanium-carbon anode material.
[0020] The preparation method of silicon-germanium-carbon anode material is as follows: Using the aforementioned germanium-supported porous hard carbon as a carrier, a silicon-germanium-carbon composite material was obtained through silane deposition. Subsequently, acetylene was introduced as a carbon source under an inert atmosphere to continuously pyrolyze and coat the above-mentioned silicon-germanium-carbon composite material, thus obtaining the silicon-germanium-carbon anode material.
[0021] In the technical solution disclosed in this invention, the deposition temperature is 400-600℃.
[0022] In the technical solution disclosed in this invention, the amount of silicon deposited is 30-60% based on the mass of the silicon-germanium-carbon composite material.
[0023] In the technical solution disclosed in this invention, the pyrolysis temperature is 550-650℃ and the pyrolysis time is 0.5-3h.
[0024] In the technical solution disclosed in this invention, the flow rate of acetylene is 0.5-2 L / min.
[0025] Compared with the prior art, the present invention has the following beneficial effects: This invention selects germanium, whose ionic / electronic conductivity is much higher than that of silicon, as the active material and loads it in a three-dimensional interconnected porous hard carbon pore. By utilizing germanium's excellent carrier migration ability, the core bottleneck of low ionic conductivity and poor rate performance inherent in silicon-based materials is fundamentally solved. At the same time, the high conductivity and abundant ion transport pathways inherent in the porous hard carbon framework form a synergistic enhancement effect with germanium, jointly constructing a highly efficient electron / ion dual continuous conduction network, thereby achieving a significant improvement in rate performance while maintaining high specific capacity. Attached Figure Description
[0026] Figure 1 This is a comparison of the electrical conductivity of the germanium-supported porous hard carbon material prepared in Example 1 and the porous hard carbon material prepared in Comparative Example 1. Figure 2 EIS comparison diagram of the silicon-germanium-carbon anode material prepared in Example 1 and the silicon-carbon anode material prepared in Comparative Example 1; Figure 3 The image shows a GITT comparison between the silicon-germanium-carbon anode material prepared in Example 1 and the silicon-carbon anode material prepared in Comparative Example 1. Detailed Implementation
[0027] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.
[0028] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.
[0029] Example 1 A method for preparing germanium-supported porous hard carbon includes the following steps: S1. Pretreatment of porous hard carbon: Weigh 100 g of coconut shell-based porous hard carbon (specific surface area 1800 m² / g, pore volume 0.89 cm³). 3 / g), placed in 2.5 L of 3 M dilute nitric acid solution, mechanically stirred at 80 °C for 4 h. After the reaction was completed, it was washed with deionized water until the filtrate was neutral, and then vacuum dried at 110 °C for 10 h to obtain acid-treated porous hard carbon. S2. Preparation of germanium source solution: In a dry beaker, slowly dissolve 20.4 g of germanium tetrachloride in 400 mL of anhydrous ethanol and stir until completely clear to prepare a 0.25 mol / L germanium source ethanol solution. S3. Impregnation and adsorption: The pretreated porous hard carbon was added to the germanium source solution, ultrasonically treated for 30 min, and then continuously stirred at room temperature for 20 h to obtain a suspension. S4. Reduction and fixation: Slowly add 500 mL of 0.5 M NaBH4 solution with pH 9 to the suspension. After the addition is complete, continue stirring the reaction at 70 °C for 3 h. Filter the solution and wash the solid product three times with ethanol. Transfer the filter cake to a tube furnace and calcine it at 400 °C at 5 °C / min under an argon-hydrogen mixed atmosphere containing 8% hydrogen. Hold the temperature for 2 h and allow it to cool naturally to room temperature. S5. Post-treatment: The calcined product was washed three times with deionized water and once with anhydrous ethanol, and then dried in a vacuum drying oven at 100℃ for 12 hours to obtain germanium-supported porous hard carbon material.
[0030] Example 2 A method for preparing germanium-supported porous hard carbon includes the following steps: S1. Pretreatment of porous hard carbon: Weigh 100g of phenolic resin-based porous hard carbon (specific surface area of 2000m²). 2 / g, pore volume 0.91cm 3 / g), placed in 2.5L of 1M dilute nitric acid solution, mechanically stirred at 60℃ for 6h. After the reaction was completed, it was washed with deionized water until the filtrate was neutral, and then vacuum dried at 100℃ for 12h to obtain acid-treated porous hard carbon. S2. Preparation of germanium source solution: In a dry beaker, dissolve 23.2g of germanium nitrate in 500mL of deionized water and stir until completely clear to prepare a 0.2mol / L germanium source aqueous solution. S3. Impregnation and adsorption: The pretreated porous hard carbon was added to the germanium source aqueous solution, ultrasonically treated for 30 min, and then continuously stirred at room temperature for 24 h. S4. Reduction and fixation: Slowly add 50 mL of 80% hydrazine hydrate to the suspension, stir and react at 60 °C for 4 h, filter, wash the solid product three times with deionized water, transfer the filter cake to a tube furnace, heat to 300 °C at 3 °C / min under an argon-hydrogen mixed atmosphere containing 5% hydrogen, and keep it at that temperature for 2 h, then cool naturally to room temperature. S5. Post-treatment: The calcined product was washed three times with deionized water and once with anhydrous ethanol, and then dried in a vacuum drying oven at 100℃ for 12 hours to obtain germanium-supported porous hard carbon material.
[0031] Example 3 A method for preparing germanium-supported porous hard carbon includes the following steps: S1. Pretreatment of porous hard carbon: Weigh 100 g of phenolic resin-based porous hard carbon (specific surface area 2100 m²). 2 / g, pore volume 0.93 cm³ 3 / g), placed in 2.5L of 1M dilute nitric acid solution, mechanically stirred at 60℃ for 6h. After the reaction was completed, it was washed with deionized water until the filtrate was neutral, and then vacuum dried at 100℃ for 12h to obtain acid-treated porous hard carbon. S2. Preparation of germanium source solution: Dissolve 10.4g of germanium oxide in 200mL of 2M sodium hydroxide solution and stir in a 60℃ water bath until completely dissolved to form a colorless and transparent sodium germanate solution. Then dilute with deionized water to a total volume of 500mL to obtain the germanium source solution. S3. Impregnation and adsorption: The pretreated porous hard carbon was added to the germanium source solution, ultrasonically treated for 30 min, and then continuously stirred at room temperature for 20 h. S4. Reduction and fixation: The impregnated mixture was filtered, and the resulting solid was vacuum dried at 110°C for 8 hours. The dried solid was transferred to a tube furnace and heated to 400°C at 5°C / min in an argon-hydrogen mixed atmosphere containing 8% hydrogen. The temperature was then held for calcination for 2 hours and allowed to cool naturally to room temperature. S5. Post-treatment: The calcined product was washed three times with deionized water and once with anhydrous ethanol, and then dried in a vacuum drying oven at 100℃ for 12 hours to obtain germanium-supported porous hard carbon material.
[0032] Example 4 A method for preparing germanium-supported porous hard carbon includes the following steps: S1. Pretreatment of porous hard carbon: Weigh 100 g of coconut shell-based porous hard carbon (specific surface area 1700 m² / g, pore volume 0.88 cm³). 3 / g), placed in 2.5L of 3M dilute nitric acid solution, mechanically stirred at 80℃ for 4h. After the reaction was completed, it was washed with deionized water until the filtrate was neutral, and then vacuum dried at 110℃ for 10h to obtain acid-treated porous hard carbon. S2. Preparation of germanium source solution: In a dry beaker, slowly dissolve 40.8g of germanium tetrachloride in 400 mL of anhydrous ethanol and stir until completely clear to prepare a 0.5mol / L germanium source ethanol solution. S3. Impregnation and adsorption: The pretreated porous hard carbon was added to the germanium source solution, ultrasonically treated for 45 min, and then continuously stirred at room temperature for 24 h to obtain a suspension. S4. Reduction and fixation: Slowly add 1000 mL of 1.0 M NaBH4 solution to the suspension, with a pH of approximately 9.5. After the addition is complete, continue stirring the reaction at 75 °C for 3.5 h. Filter the solution, wash the solid product three times with ethanol, transfer the filter cake to a tube furnace, and calcine it at 5 °C / min in an argon-hydrogen mixed atmosphere containing 10% hydrogen for 2 h. Allow it to cool naturally to room temperature. 5. Post-treatment: The calcined product was washed three times with deionized water and once with anhydrous ethanol, and then dried in a vacuum drying oven at 100℃ for 12 hours to obtain germanium-supported porous hard carbon material.
[0033] Example 5 A method for preparing germanium-supported porous hard carbon includes the following steps: S1. Pretreatment of porous hard carbon: Weigh 100 g of coconut shell-based porous hard carbon (specific surface area 1800 m²). 2 / g, pore volume 0.89cm 3 / g), placed in 2.5L of 3M dilute nitric acid solution, mechanically stirred at 80℃ for 4h. After the reaction was completed, it was washed with deionized water until the filtrate was neutral, and then vacuum dried at 110℃ for 10h to obtain acid-treated porous hard carbon. S2. Preparation of germanium source solution: In a dry beaker, slowly dissolve 20.4 g of germanium tetrachloride in 400 mL of anhydrous ethanol and stir until completely clear to prepare a 0.25 mol / L germanium source ethanol solution. S3. Impregnation and adsorption: The pretreated porous hard carbon was added to the germanium source solution, ultrasonically treated for 30 min, and then continuously stirred at room temperature for 20 h. S4. Reduction and fixation: Slowly add 500 mL of 0.5 M NaBH4 solution to the suspension, with a pH of approximately 9. After the addition is complete, continue stirring the reaction at 70 °C for 3 h. Filter the solution, wash the solid product three times with ethanol, transfer the filter cake to a tube furnace, and calcine it at 400 °C at 5 °C / min under an argon-hydrogen mixed atmosphere containing 8% hydrogen for 2 h. Allow it to cool naturally to room temperature. S5. Post-treatment: The calcined product was washed three times with deionized water and once with anhydrous ethanol, and then dried in a vacuum drying oven at 100℃ for 12 hours to obtain germanium-supported porous hard carbon material.
[0034] Comparative Example 1 A method for pretreating porous hard carbon includes the following steps: Weigh 100g of coconut shell-based porous hard carbon (specific surface area 1800m²). 2 / g, pore volume 0.89cm 3 The acid-treated porous hard carbon was placed in 2.5 L of 3M dilute nitric acid solution and mechanically stirred at 80 °C for 4 h. After the reaction was completed, the carbon was washed with deionized water until the filtrate was neutral. Then, it was vacuum dried at 110 °C for 10 h to obtain the acid-treated porous hard carbon.
[0035] 100g of the germanium-supported porous hard carbon material prepared in Example 1 was weighed and placed in a rotary kiln. Nitrogen gas was introduced as a protective gas (0.5L / min). After heating to 500℃ and stabilizing, silane (SiH4) was introduced at a flow rate of 0.5 L / min. The deposition time was controlled to be 108 min, so that the amount of silicon deposited reached 40% of the total mass of the composite material. After the silane deposition was completed, the furnace temperature was raised to 650℃ under argon protection. Then, acetylene was introduced as a carbon source at a flow rate of 1L / min, and the pyrolysis coating was continued for 1 h to obtain the silicon-germanium-carbon anode material.
[0036] 100g of the germanium-supported porous hard carbon material prepared in Example 2 was weighed and placed in a rotary kiln. Nitrogen gas was introduced as a protective gas (0.5L / min). After heating to 500°C and stabilizing, silane (SiH4) was introduced at a flow rate of 0.5 L / min. The deposition time was controlled to be 68 min, so that the amount of silicon deposited reached 30% of the total mass of the composite material. After the silane deposition was completed, the furnace temperature was raised to 600°C under argon protection. Then, acetylene was introduced as a carbon source at a flow rate of 0.5 L / min, and the pyrolysis coating was continued for 3 h to obtain the silicon-germanium-carbon anode material.
[0037] 100g of the germanium-supported porous hard carbon material prepared in Example 3 was weighed and placed in a rotary kiln. Nitrogen gas was introduced as a protective gas (0.5L / min). After heating to 500℃ and stabilizing, silane (SiH4) was introduced at a flow rate of 0.5L / min. The deposition time was controlled to be 108min, so that the amount of silicon deposited reached 40% of the total mass of the composite material. After the silane deposition was completed, the furnace temperature was raised to 580℃ under argon protection. Then, acetylene was introduced as a carbon source at a flow rate of 1L / min, and the pyrolysis coating was continued for 1h to obtain the silicon-germanium-carbon anode material.
[0038] 100g of the germanium-supported porous hard carbon material prepared in Example 4 was weighed and placed in a rotary kiln. Nitrogen gas was introduced as a protective gas (0.5L / min). After heating to 500℃ and stabilizing, silane (SiH4) was introduced at a flow rate of 0.5 L / min. The deposition time was controlled to be 108 min, so that the amount of silicon deposited reached 40% of the total mass of the composite material. After the silane deposition was completed, the furnace temperature was raised to 650℃ under argon protection. Then, acetylene was introduced as a carbon source at a flow rate of 1L / min, and the pyrolysis coating was continued for 1 h to obtain the silicon-germanium-carbon anode material.
[0039] 100g of the germanium-supported porous hard carbon material prepared in Example 5 was weighed and placed in a rotary kiln. Nitrogen gas was introduced as a protective gas (0.5L / min). After heating to 500℃ and stabilizing, silane (SiH4) was introduced at a flow rate of 0.5 L / min. The deposition time was controlled to be 240 min, so that the amount of silicon deposited reached 60% of the total mass of the composite material. After the silane deposition was completed, the furnace temperature was raised to 650℃ under argon protection. Then, acetylene was introduced as a carbon source at a flow rate of 2L / min, and the pyrolysis coating was continued for 0.5 h to obtain the silicon-germanium-carbon anode material.
[0040] 100g of the acid-treated porous hard carbon prepared in Comparative Example 1 was weighed and placed in a rotary kiln. Nitrogen gas was introduced as a protective gas (0.5L / min). After heating to 500℃ and stabilizing, silane (SiH4) was introduced at a flow rate of 0.5 L / min. The deposition time was controlled to be 108 min, so that the amount of silicon deposited reached 40% of the total mass of the composite material. After the silane deposition was completed, the furnace temperature was raised to 650℃ under argon protection. Then, acetylene was introduced as a carbon source at a flow rate of 1L / min, and the carbon was continuously pyrolyzed and coated for 1 h to obtain the silicon-carbon anode material.
[0041] The conductivity of the germanium-supported porous hard carbon material prepared in Example 1 and the porous hard carbon material prepared in Comparative Example 1 were tested. The specific experimental steps are as follows: Weigh 0.1g to 0.5g of powder sample and pour it into the cavity tower of a four-probe powder resistivity meter; turn on the power switch of the resistivity meter and preheat for 30 min; lock the prepared sample and cavity tower in the fixed support, open the testing software, input the relevant information, click start, and the testing software automatically calculates the conductivity of the sample powder. The experimental results are as follows. Figure 1 As shown, from Figure 1 As can be seen, the powder conductivity of germanium-supported porous hard carbon material is significantly improved compared to that of porous hard carbon material.
[0042] The silicon-germanium-carbon anode material prepared in Example 1 and the silicon-carbon anode material prepared in Comparative Example 1 were subjected to EIS testing. The specific experimental steps are as follows: a half-cell was assembled with the silicon-carbon anode material, and the open-circuit voltage was tested to confirm that it was >2V. The cell was then left to stand for 6 hours. An electrochemical workstation was used for testing, with the three electrodes connected to the half-cell. The cell was placed in a constant temperature environment of 25±1℃. The constant potential EIS mode was selected, with the initial potential set to the open-circuit voltage and the frequency range 10. 5 ~10 - 2Hz, AC amplitude 5-10mV, begin testing. Test results are as follows: Figure 2 As shown, from Figure 2 As can be seen from the results, the silicon-germanium-carbon anode material prepared in Example 1 has lower ohmic impedance and charge transfer impedance, which proves that it has higher ionic and electronic conductivity.
[0043] The silicon-germanium-carbon anode material prepared in Example 1 and the silicon-carbon anode material prepared in Comparative Example 1 were subjected to GITT testing. The specific experimental steps are as follows: A half-cell was assembled using the silicon-carbon anode material, and the open-circuit voltage was confirmed to be >2V. The cell was then allowed to stand for 6 hours. An electrochemical workstation was used for testing, with the three electrodes connected to the half-cell. The cell was placed in a constant temperature environment of 25±1℃. A constant current intermittent mode was selected, with a current density of 0.01-0.05C and a titration time of 10-30 minutes. After intermittent standing for 30-60 minutes, the test was started. The experimental results are as follows: Figure 3 As shown, from Figure 3 As can be seen from the data, the silicon-germanium-carbon anode material prepared in Example 1 has a larger lithium-ion diffusion coefficient, which proves that it has a higher ionic conductivity.
[0044] The electrochemical performance of the anode materials prepared in Examples 1-5 and Comparative Example 1 was tested. The specific steps are as follows: a half-cell was assembled with silicon-carbon anode material, and the open-circuit voltage was tested to confirm that it was >2V. The cell was then left to stand for 6 hours. The battery was tested using a Blue Electric testing system and placed in a constant temperature environment of 25±1℃. The constant current charge-discharge mode was selected, and the gradient was set according to 0.1C→0.5C→1C→2C→4C, with 1 charge and 1 discharge per rate. The upper and lower voltage limits were set to 1.5V / 0.005V. The test was then started, and the test results are shown in Table 1.
[0045] Table 1. Electrochemical performance test results for each group As can be seen from Table 1, the silicon-germanium-carbon anode materials prepared in Examples 1-5 have superior rate performance compared to the silicon-carbon anode material prepared in Comparative Example 1.
[0046] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.
Claims
1. A method for preparing germanium-supported porous hard carbon, characterized in that, Includes the following steps: S1. The porous hard carbon is immersed in an acid solution, heated and stirred, and then filtered, washed and vacuum dried to obtain pretreated porous hard carbon. S2. The pretreated porous hard carbon is ultrasonically dispersed in a germanium source solution and stirred. Then, a reducing agent is added dropwise, and the reaction is heated. After the reaction is completed, the precursor is obtained by filtration, washing, and drying. S3. The precursor is calcined in a reducing atmosphere. After calcination, it is cooled to room temperature, washed, and vacuum dried to obtain germanium-supported porous hard carbon.
2. The preparation method according to claim 1, characterized in that, In step S1, the heating and stirring treatment temperature is 60-90℃, and the heating and stirring treatment time is 1-6h.
3. The preparation method according to claim 1, characterized in that, In step S2, the ratio of pretreated porous hard carbon to germanium source solution is 100g:300-600mL, and the concentration of germanium source solution is 0.1-0.5mol / L.
4. The preparation method according to claim 1, characterized in that, In step S2, the germanium source is selected from germanium tetrachloride, germanium nitrate, or germanium oxide.
5. The preparation method according to claim 1, characterized in that, In step S2, the reducing agent is selected from NaBH4 solution or hydrazine hydrate.
6. The preparation method according to claim 1, characterized in that, In step S2, the pH of the reaction system is controlled at 8-10, the temperature of the heating reaction is 60-80℃, and the heating reaction time is 2-4h.
7. The preparation method according to claim 1, characterized in that, In step S3, the volume fraction of H2 in the reducing atmosphere is 5-10%.
8. The preparation method according to claim 1, characterized in that, In step S3, the calcination temperature is 300-500℃ and the calcination time is 1-3h.
9. Germanium-supported porous hard carbon prepared by any one of claims 1-8.
10. The application of germanium-supported porous hard carbon as described in claim 9 in battery anode materials.